BRC-BIO: Determining the neural mechanisms regulating photostimulation of migratory physiology and behavior

这个项目将让我们了解鸣鸟的大脑如何利用环境信息来计算季节性迁徙的时间。与留鸟不同，候鸟特别容易受到环境变化的影响，因为它们每年必须在多种环境中迁徙。它们必须在不直接了解目的地环境条件的情况下，根据广义的季节性线索，特别是日长、光周期的季节性变化，来计算迁徙旅程的时间，以适当地确定出发的时间。然而，我们仍然对大脑中将光周期信息处理成支持迁移所必需的复杂的生理和行为变化的路径知之甚少。特别是，迁徙和繁殖准备都依赖于相同的季节性光周期信号，这限制了我们理解迁徙时间如何被控制的能力。该项目将使用以前确定的光照制度来分离迁徙生理和生殖，以便确定那些特定于迁徙的神经机制。通过了解动物如何利用光周期信号来确定迁徙的时间，我们将能够更好地预测候鸟可以灵活应对的环境变化的范围，为保护工作提供信息。该项目将为多名本科生创造资助研究的机会，通过减少在研究和有偿工作之间的选择，扩大能够参与本科生研究的学生群体。在该项目开发的设备和资源的基础上，将开发一系列关于候鸟生理和行为的公共宣传资源，供在当地和整个阿拉巴马州墨西哥湾沿岸社区的活动中使用。该项目由BRC BIO计划和既定的激励竞争研究计划(EPSCoR)共同资助。该项目解决了鸣鸟如何从它们的环境中探测光信号并将其整合到支持春季迁徙所需的一系列复杂的生理、形态和行为变化中的基本问题。光周期变化被认为是控制许多物种迁徙时机的预测性线索。然而，移民时机背后的机制仍然不清楚。这是因为季节性迁徙和繁殖都依赖于春季光周期的增加作为信号，需要大脑中的甲状腺激素信号发生。迁移机制和生殖机制之间的重叠限制了旨在确定神经机制的观察性研究的效用，以及甲状腺基因敲除等简单操控努力的有效性。该项目利用先前建立的低强度绿光范例，在研究得很好的白冠麻雀系统中，在不触发生殖生理的情况下，光刺激春季迁徙的发展。然后，该项目将通过开发用于免疫组织化学的定制抗体来定位大脑深层光感受器的神经表达，这些光感受器能够检测到这种低强度的绿光信号。然后通过多靶点原位杂交分析，确定神经甲状腺激素信号的迁移特异性变化。最后，通过AAV2病毒载体介导的shRNAi敲除大脑中的视蛋白表达，然后使用绿光范式刺激迁移，将测试可能的光感受器候选在调节迁移生理中的直接作用。这项工作将为迁徙计时的神经机制和潜在可塑性提供新的见解。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will allow us to understand how the brains of songbirds use environmental information to time seasonal migrations. Unlike resident species, migratory birds are particularly susceptible to environmental change as they must move through multiple environments each year. They must time migratory journeys without direct knowledge of environmental conditions at their destination, relying on generalized seasonal cues, specifically the seasonal change in day length, photoperiod, to appropriately time departure. However, we still know very little about the pathways in the brain that process photoperiod information into the complex changes in physiology and behavior necessary to support migration. In particular, the shared reliance of both migration and preparation for reproduction on the same seasonal photoperiod cues has limited our ability to understand how migratory timing is controlled. This project will use previously identified lighting regimes to isolate migratory physiology from reproduction in order to identify those neural mechanisms specific to migration. By understanding how animals use photoperiod cues to time migration we will be better able to predict the scope of environmental change to which migratory birds can flexibly respond, informing conservation efforts. This project will create funded research opportunities for multiple undergraduate students to broaden the population of students able to participate in undergraduate research by alleviating the choice between research and a paying job. Building on the equipment and resources developed by this project, a series of public outreach resources on migratory bird physiology and behavior will be developed for use at events both locally and throughout the Alabama Gulf Coast community. The project was jointly funded by the BRC BIO program and the Established Program to Stimulate Competitive Research (EPSCoR).This project addresses the fundamental questions of how songbirds detect and integrate photic cues from their environment into the complex array of changes in physiology, morphology, and behavior necessary to support spring migration. Photoperiod changes are well established as a predictive cue controlling migratory timing for many species. However, the mechanisms underlying timing of migration remain obscured. This is because both seasonal migration and reproduction both rely on increasing spring photoperiod as a cue and require thyroid hormone signaling within the brain to occur. This overlap between migratory and reproductive mechanisms has limited the utility of observational studies that aim to identify neural mechanisms, as well as the efficacy of simple manipulative efforts such as thyroid knockouts. This project leverages a previously established low intensity green light paradigm to photostimulate the development of vernal migration without triggering reproductive physiology in the well-studied white-crowned sparrow system. The project will then localize neural expression of deep brain photoreceptors capable of detecting this low intensity green light cue by developing custom antibodies for immunohistochemistry. Then through multi-target in situ hybridization analysis, it will identify migration specific changes in neural thyroid hormones signaling. Finally, the direct role of putative photoreceptor candidates in regulating migratory physiology will be tested by AAV2 viral vector-mediated shRNAi knockdown of opsin expression in the brain followed by stimulation of migration using the green light paradigm. This work will provide novel insight into the neural mechanisms and the potential plasticity of migratory timing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.